Immunomodulatory agents are used to produce immune responses in subjects. It is at times advantageous to attach such agents to delivery vehicles. Currently, known attachment chemistries often require certain reactive groups, utilize certain activation steps for attachment to occur, and/or result in conjugates that do not exhibit optimal properties. There is a need, therefore, for new methods for the attachment of immunomodulatory agents to delivery vehicles as well as a need for the resulting conjugates that exhibit desired properties.